Harnessing genomics for early cancer detection, risk stratification and prevention.

Therapeutic advances have improved cancer outcomes, but early-stage detection remains the single most important determinant of favorable prognoses across many cancer types. Cancer genomics has yielded detailed maps of somatic mutation and methylation patterns characteristic of different cancers, enabling the development of assays to detect mutation-bearing tumor-derived DNA in tissue biopsies, blood and other body fluids at the earliest stages of disease. In parallel, it has also become clear that small clones bearing cancer-associated mutations arise commonly in histologically normal tissues, a phenomenon that becomes universal in proliferative tissues with age but leads to cancer in only a small minority of individuals. This review article outlines established strategies for early cancer detection and highlights emerging insights into the genetics of precancerous mutant clones that have led to the recent development of prognostic frameworks for identifying high-risk individuals, making it increasingly possible to intercept evolving cancer at a premalignant or early malignant stage, when interventions are most effective.